Short-Term Effects of Mechanical Land Treatments on Soil Stability and Wind Erosion in Dryland Ecosystems

Throughout western North America, resource managers are engaged in efforts to restore wildlands degraded by effects of land use, invasive exotic plants, and altered fire regimes. Funding provided by federal programs including the National Fire Plan, the Healthy Forests Initiative, and the Healthy Lands Initiative has driven a sharp increase in the number and extent of land treatments designed to enhance ecosystem resistance and resilience to fire, resistance to invasive exotic plants, native plant diversity, habitat quality for wildlife, and forage production for livestock. Soil stabilization often is identified as an objective of land treatments, yet little information is available to allow an examination of treatment effects on soil stability, wind erosion, and how these vary among different types of treatments, soils, and environmental conditions. This paper presents preliminary results from two projects designed to address these information needs. In the eastern Great Basin, research is being conducted to evaluate the effectiveness of post-fire stabilization treatments in a portion of the 147,000-ha Milford Flat Fire -- the largest wildfire ever to occur in Utah. On the Colorado Plateau, research is being conducted in conjunction with a habitat-restoration project in a sagebrush-steppe ecosystem. In this latter study, rates of eolian soil movement measured with BSNE dust samplers during the first year following treatment ranged from 1.8 to 96.6 times greater than rates measured in untreated sagebrush. Differences in wind erosion among treatments were related to treatment effects on soil aggregate stability, vegetation cover and structure, and fractional cover of bare ground. Intended increases in the cover and diversity of herbaceous vegetation have yet to be achieved. Results confirm the need for managers to evaluate risks of accelerated soil erosion when planning mechanical land treatments - particularly in the context of changing climatic conditions that may reduce the likelihood of treatment success.